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Mercury Marine 4.2L 370 TDI

577 lb-ft of Torque from a Twin-Turbo V-8 Diesel Engine for the Water

Oct 3, 2015
Photographers: Courtesy of Manufacturer
Mercury Marine's 4.2L 370 TDI diesel engine is packed with technology, including twin variable-geometry turbochargers that help it produce 370 hp and 577 lb-ft of torque. The 90-degree V-8 is sourced from Volkswagen (hence the "TDI" in the model name), has heads made of aluminum, and uses a block made from compacted graphite iron that helps keep the dry weight to just 836 pounds. Fueling is accomplished using a Bosch high-pressure common-rail system with Piezo-actuated injectors with built-in pressure sensors.
Turbocharged air is fed through an air-to-water intercooler that uses seawater/freshwater in the heat exchanger; "raw water" is also used to cool the exhaust risers. Other than that, the engine is kept completely separate from the potentially corrosive effects of external water sources through its use of "closed-cooled" systems for the engine, oil, exhaust manifolds, and turbochargers. The twin-propeller MerCruiser SeaCore Bravo Three XR Diesel propulsion drive shown here weighs 240 pounds, and Mercury says it features best-in-class shifting along with dual counter-rotating propellers that provide more "bite" and better steering agility than a single-prop setup.
Photo 2/2   |   The Mercury Marine 4.2L 370 TDI is a diesel V-8 engine with twin variable-geometry turbochargers that makes 370 hp and 577 lb-ft of torque. It's shown here fitted with a MerCruiser SeaCore Bravo Three XR Diesel propulsion drive that uses dual counter-rotating, stainless steel propellers.
Mercury Marine 4.2L 370 TDI
Displacement: 4.2L (252ci)
Layout: V-8 90-degree
Head material: Aluminum
Block material: Compacted graphite iron
Bore x stroke: 3.27x3.74 inches
Compression ratio: 16.4:1
Power: 370 hp
Torque: 577 lb-ft at 2,750 rpm
Induction: Twin variable-geometry turbochargers
Aftercooling: Air-to-water intercooler
Fueling: High-pressure common-rail with Piezo-actuated injectors and pressure sensors
Exhaust: Closed-cooled manifolds, closed-cooled turbochargers, and water-cooled risers
Noise level: 70 dB
Emissions: EPA Tier 3, RCD 2, IMO 2, and BSO 2
Length: 3 feet, 11.5 inches
Width: 2 feet, 9 inches
Height: 2 feet, 9 inches
Weight: 836 pounds
Propulsion drive unit: MerCruiser SeaCore Bravo Three XR Diesel
Drive type: Sterndrive with dual counter-rotating stainless steel propellers
Gear ratio: 1.65:1/1.81:1
Propulsion system weight: 240 pounds


Mercury Marine
Fond du Lac, WI 54936
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